The traditional outlet device employs a manual control switch. There are still weak points in it: firstly, as it is manual control, the switch is easily worn, the service life of the switch is short; secondly, in some situation, such as in the public, it will make the user's hands dirty; thirdly, it's difficult to use by some people, such as blind men and children.
To solve above problems and disadvantages, there are inductive control switch applied in the outlet device, such as infrared ray inductive switch. This method solves the problems of the traditional outlet device, there are disadvantages: user has to reach his hand to the inductive area of the inductive switch. The inductive area is limited, making the usage inconvenient.